Stent grafts have been devised for endovascular deployment to bypass a diseased portion of a vessel and such stent grafts can be deployed into body vessels such as the aorta. Where there are branches from the body vessel such as the coeliac artery, the superior mesenteric artery and the renal arteries it is desirable to have a fenestration in the stent graft so that an extension arm can be placed through the fenestration to allow flow into the branch vessel.
In the renal and suprarenal region of aorta, the use of stent graft with fenestrations in the wall of the stent graft provides difficulty for catheterisation and sealing and there have been proposed stent grafts with internal branches into which can be deployed a side arm extension to extend from the internal branch of the stent graft into a branch vessel and so that the side arm extension can seal with in the internal branch.
In some regions of the aorta such as the thoracic arch and the infra renal region there is often insufficient length of stent graft proximally of the fenestration to allow an internal arm of sufficient length to be used. If the internal arm is made too short then there is insufficient length for sealing of the extension arm.
It is the object of this invention to provide a solution to this problem or at least to provide the practitioner with an alternative stent graft construction.
The invention will be particularly discussed in relation to deployment of a stent graft into the renal and suprarenal regions of the aorta for deployment of a stent graft into coeliac artery, the superior mesenteric artery and the renal arteries, however, the invention is not so limited and may be applied to other regions where there are branches from a main graft such as in the thoracic arch.
Throughout this specification the term distal, when used with respect to a portion of the aorta, a deployment device or a prosthesis, means the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart and the term proximal means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood.